Method of, and apparatus for, delivering yarns to textile machines

ABSTRACT

Associated with a knitting machine, apparatus for imparting false twist to yarns and delivering them to the machine. Knitting elements in the machine draw on the yarn intermittently and at varying speeds. Apparatus comprises a processing unit including four assemblies of false twist heads and heaters mounted above the machine on a frame surrounding the latter. Each assembly processes two yarns and comprises four twist heads and three heaters, the latter being arranged in a common vertical plane in positions defining three sides of a rectangle, with a twist head disposed at each corner thereof. Movable yarn guides are provided to lift the yarns away from the heaters when the knitting machine stops.

United States Patent AXAXXX 525.45U 20234 1 1 A ///77 6665 666 W W 6 3,139,741 7/1964 Strub 3,153,923 10/1964 Burleson 3,148,520 9/1964 Biggers...... 3,166,822 1/1965 Starkie 3,451,206 6/1969 Mackintosh... 3,482,384 12/1969 Berger..........................

g machine, apparatus delivering them to the aw on the yarn above the Primary ExaminerDonald E. Watkins Attorney-Larson, Taylor and Hinds ABSTRACT: Associated with a knittin for imparting false twist to yarns and machine. Knitting elements in the machine dr intermittently and at varying speeds.

Apparatus comprises a processing unit including four assemblies of false twist heads and heaters mounted machine on a frame surrounding the latter. Each assembly processes two yarns and comprises four twist heads and three heaters, the latter being arranged in a common vertical plane in positions defining three sides of a rectangle, with a twist head disposed at each corner thereof. Movable yarn guides are provided to lift the yarns away from the heaters when the knitting machine stops.

57/34 11s, 57/7745, 66/125 A D0lh 7/92,

Loughborough, Leicestershire, England Priority Dec. 11,1968, June 14, 1968 Great Britain 58878/68, 28304/68 [54] METHOD OF, AND APPARATUS FOR,

DELIVERING YARNS T0 TEXTILE MACHINES 16 Claims, 10 Drawing Figs.

[51] [50] Field of HS, 77.3, 77.45; 66/125 A, 202

[56] References Cited UNITED STATES PATENTS 3,066,473 12/1962 Maeda.......................... 3,120,049 2/1964 Spurgeon.....................

METHOD OF, AND APPARATUS FOR, DELlVERING YARNS TO TEXTELE MACHINES This invention relates to the delivery of yarns to knitting or other textile machines.

The expression yam where used in this specification is intended to include threads or the like.

The conventional practice is for yarns after being produced, to be processed, e.g. bulked or crimped, and then wound on to bobbins, cones, cheeses or the like for supply to the ultimate user thereof, e.g. a hosiery or textile manufacturer. In use, the yarns are delivered to textile machines directly from the bobbins or the like. This practice, however, has various disadvantages which will be apparent from the following description of a particular environment in which it applies.

It is a known practice, after continuous filament thermoplastic yarns have been produced in the flat (i.e. un' processed) form to texturize the same in a specialized process known as false twisting. Such a process is one in which a synthetic yarn is twisted to the extent of a relatively large number of turns per inch by twisting means and is heat set. By a relatively large number of turns is, for example, meant any appropriate number in the range from 80-120 per inch: thus, any yarn from, say, -40 deneirs would have imparted to it about 100 turns per inch. In any event, the twisting and heat setting of this yarn results in it bulking up and becoming lively upon subsequent recovery. A false twisted yarn is accordingly a stretch yarn suitable for the production of stretchable fabrics and hosiery, e.g. stockings and tights.

Following such a false twisting operation, the yarns are wound on to bobbins, cones, cheeses or the like for supply to the ultimate user thereof, e.g. a hosiery or textile manufacturer. In use, the false twisted yarns are delivered to textile machines directly from the bobbins or the like. This practice, however, has various disadvantages which will be apparent from the following description of a particular environment in which it applies. 7

Now it is desirable for economic and technical reasons that the processing of the yarn should be performed immediately before it is delivered to a textile machine.

A large proportion of the cost of textured yarn supplied by a processing organization to a textile manufacturer consists of the price of processing and if flat (i.e., unprocessed) yarn could be delivered directly from a processing unit to a textile machine, it is obvious that a great economic advantage would be gained.

Since yarn supplied to manufacturers is processed on different frames (or different spindles of the same frame) and since it is not practical to segregate each batch through the chain of supply, faulty work is regularly occasioned through the constituent yarns in a garment or fabric not matching. Often the fault does not make itself apparent until the garment or fabric is dyed, when the dye affinity of one yarn is often different from that of another, and so stripiness or other defects show up.

It will be appreciated that in many instances such, for example, as in the manufacture of ladies hose, yarn is drawn into the knitting machine intermittently and at varying speeds. However, since yarn is delivered at a constant rate from a processing unit, it cannot be fed directly to the machine from the unit.

The object of the invention is to overcome these disadvantages by the provision of a novel method of delivering yarn to a knitting or other textile machine.

According to the method of the invention, the yarn is fed to the machine from a processing unit intimately associated therewith and is drawn upon by relevant instruments or elements of the machine intermittently and at varying speeds.

According to one manner of performing this method, the processing unit continuously processes yarn which is initially fed into an associated store from which the processed yarn can thereupon be drawn upon by the machine, intermittently and at varying speeds.

According to a preferred manner of carrying out the method, the yarn is fed into the machine directly from the processing unit which latter, as already stated, is itself intermittently operated.

The invention also provides apparatus for delivering yarn to a knitting or other textile machine, comprising a processing unit intimately associated with the latter, and from which yarn is fed to the machine, the yarn being drawn upon by relevant instruments or elements of the machine intermittently and at varying speeds.

in the direct method of delivering continuous filament thermoplastic yarn to a knitting or other textile machine, the processing unit, which includes yarn bulking, e.g. twisting or crimping, means and associated heaters, is adapted to convert the yarn from an initially flat condition into a heatset twisted or any other suitable bulked form, and the act of stopping and starting the processing unit is made possible by the provision of means of any appropriate character for effecting relative movement between the yarns and heaters to respectively bring the latter into and out of a working relationship and enable the supply of yarn to be performed intermittently and at varying speeds. That is to say, the bulking process can be safely stopped providing the yarn and heaters are quickly separated, and can be started up again without detriment so long as the latter are just as quickly returned to their working relation ship.

It is primarily the intention that the above-mentioned bulking means be constituted by twist heads. These heads may be of the kind comprising a rotary annular component of unitary fonn having a relatively small central opening which extends axially and merges into and connects ends (constituting the opposite sides of the twist head), these ends being trumpetshaped and each presenting an outwardly flared convex friction engendering surface of annular form extending around an arc of substantially the said surfaces and the intermediate central opening connecting them being so related that a yarn or thread caused to travel diagonally through the component in a direction transverse to its axis of rotation not only has its respectively opposite sides frictionally contacted by frictionengendering surface portions moving in respectively opposite directions, but is supported for the major part of the distance both between the outer perimeter of the trumpet-shaped flare at one side of the head and the geometrical center of the latter and also between the said center and the outer perimeter of the similar flare at the opposite side of the head, whereby the yarn is fully controlled within the twist head and the twist generated in the yarn is prevented from springing through the twist head and so being nullified.

In the preferred form of twist head of the character specified in the last preceding paragraph, as disclosed in my U.S. Pat. Application Ser, No: 819,160, filed concurrently herewith, now U.S. Pat. No. 3,537,250, issued Nov. 3, 1970, the outwardly flared annular convex surface of each trumpetshaped end of the twist head instead of being wholly or mainly of a uniform friction-engendering surface, is adapted to present only a comparatively narrow and thus localized effective friction-engendering surface area, the remainder of the convex surface being so smooth that the friction engendered thereby is practically negligible. In other words, the said remainder of the convex surface is, for all practical intents and purposes a substantially nonfriction surface.

Quick starting and stopping of the twist heads may be facilitated by driving them independently. The trumpetshaped ends of the rotary annular components constituting the twist heads may, in fact, form extensions of the rotors of separate electric motors as is more specifically described hereinafter.

As far as I am aware, this is the first time that a textile yarn has been passed through the rotor of an electric motor for the purpose of having twist imparted thereto to a degree determined by the speed of the rotor.

In one embodiment, each twist head may be so formed that a yarn entering it in one direction and in the course of being twisted by that head can leave the latter either in the same general direction or in a direction at an angle with respect to the first, the heads being so arranged in relation to the heaters as to cause a yarn leaving a twist head and about to enter and pass through or over a heater, to change direction whilst the twist in the yarn continues to build up in contradistinction to being suppressed.

In order that the invention may be more clearly understood and readily carried into practical effect, specific embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a front perspective view of a yam-processing unit according to this invention mounted on a frame positioned around a knitting machine to which processed yarn is being delivered from the unit,

FIG. 2 is a front perspective view of the unit of FIG. 1 separate from the machine and in a collapsed condition,

FIG. 3 is an enlarged perspective view with parts broken away, of the processing unit,

FIG. 4 is a detail view, partly in vertical cross section, of one set of heaters and yarn twist heads employed in the processing unit,

FIG. 5 is a cross-sectional view of one of the twist heads employed in the unit,

FIG. 6 is a partly exploded general perspective view of the twist head of FIG. 5,

FIG. 7 is a cross-sectional view of one of the compensator units employed in the processing unit,

FIG. 7a is a view similar to FIG. 7, os a modified form of compensator unit, and

FIGS. 8 and 9 are cross-sectional views of a modified heater arrangement.

Referring initially to FIG. 1, a conventional 8 feed hose knitting machine is shown diagrammatically at K. Surrounding the machine is a tubular metal frame F on top of which is mounted a yarn processing unit P. The frame F carries bobbins 1 having unprocessed, i.e. flat, yarns Y wound thereon for feeding to the machine K via the processing unit P which bulks the yarn. As can be seen, the frame F in this embodiment carries eight bobbins I, one for each machine feed.

This frame comprises four uprights 2 which are connected at their lower ends by three stays 3 arranged to define three sides of a rectangle. Each end of the frame is provided with a supplementary stay 4 about each end stay 3, and a crossbar 5 between the upper ends of uprights 2. Slidably mounted on each upright 2 is a tubular member 6, the upper ends of these members being connected by a rectangular subframe 7 on which the processing unit P is mounted. Each pair of bobbins I is mounted on a bar 8 pivoted at one end to the lower end of one of the members 6. Thus, the upper part of the frame F carrying the processing unit P and bobbins 1 is vertically slidable on the lower part of the frame.

Mounted on each crossbar 5 of the frame is a vertical plate 9 which carries a pair of rotatable drums 10, inside each of which is a coil spring (not shown) arranged to bias the drum in one rotational direction. In this embodiment, the left hand drum 10 is biased in the anticlockwise and the right-hand drum in the clockwise direction as shown. Each drum has wound therearound, a tape 11 which is fixed to the drum at one end and at the other end is fixed to a crossbar 12 between the lower ends of tubular members 6. The combined strengths of all four of the springs biassing the drums I0 is equal to the total weight of the processing unit P so that the upper part of the frame carrying the unit can easily be pulled downwards against the spring action by an operative to bring the unit P into easy reach when it requires attention. For example, the unit P may weigh l pounds, in which case the two springs at each side of the frame exert a combined pull of 60 pounds. Of course, the frame will be drawn forwards from around the machine before the unit P is lowered in this way.

Locking means of any appropriate character (not shown) may be provided, if desired, to retain the frame in its lowered condition. For example, the uprights 2 and tubular members 6 could be apertured at appropriate locations so that locking pins could be inserted through the aligned apertures.

Reference will now be made more particularly to FIGS. 3 and 4 which illustrate the processing unit P in more detail. This unit is designed to simultaneously process eight yarns Y being fed to the machine K from the bobbins I and comprises four assemblies A of heaters and twist heads, each for crimping two yarns. Each of these assemblies comprises three heaters 13 arranged in a common vertical plane in positions defining three sides of a rectangle, with a twist head 14 disposed at each corner thereof, i.e. a twist head is located at each opposite end of a heater. As can be seen, two heaters 13 are disposed vertically with the third in a horizontal position between the upper ends of the vertical heaters. Each yarn to be processed enters the unit P through the outer bottom twist head, passes upwardly over the outer heater and through the top outer twist head. From here it runs along the horizontal heater, through the top inner twist head, down over the inner heater, through the bottom inner twist head and downwardly to the machine K. The aforesaid two yarns to be crimped in each heater/twist head assembly A enter each successive twist head 14 from opposite sides and pass over the heaters 13 side by side.

The heaters 13 are of conventional form and each comprise a support 15 made of asbestos packing on which is mounted a heating plate 16. The upper surface of the plate is conventionally covered with a layer of chromium plated coppernickel. However, this is expensive and it is proposed, according to the invention, to cover the heater with two parallel tracks 17 of fiber-glass tape impregnated with polytetrafluoroethylene on which the yarns Y run. As can be seen from FIG. 4, the surface of the heater is curved from end to end to provide a smooth path for the yarn Y.

Each heater has a cover 18 provided internally with two parallel slots 19 to accommodate the yarn. The covers are mounted on the heaters through a pair of captive retaining pins 20 which are slidably received in holes in the latter so that each cover is captively movable between a first position in which the yarns Y are enclosed thereby and a second position clear of the heaters.

FIGS. 5 and 6 of the drawings illustrate in detail, the form of the twist heads 14 employed in the unit P. It is however, to be understood, that any convenient form of twist head other than that specifically illustrated, could be used.

The illustrated twist head 14 is constituted by a rotary annu lar component comprising two coaxially and oppositely disposed elements 2] which are rigidly connected together by an embracing bush 22 having combined therewith, the inner rotary races 23a of ball bearings 23. The outer stationary races 23b of these bearings are mounted within two spaced housing plates or blocks 24 (FIG. 6). The central portion of the twist head thus extends axially and merges into and connects the trumpet-shaped ends 21a forming the opposite sides of the head. A relatively small central opening 25 in the said central portion merges into and connects outwardly flared convex surfaces 21b of annular form presented by the interiors of the trumpet-shaped ends 210. The surface of each end of axially extending central opening 25 and the outwardly flared convex surface of the adjoining trumpet-shaped end 210 extend around an arc of substantially The middle portion of the central opening 25 is enlarged at 25a by virtue of recessing the inner end of each of the two abutted elements 21.

The outwardly flared annular convex surface 21b of each of the trumpet-shaped ends 21a of the twist head 14 is adapted to present only a comparatively narrow and thus localized friction-engendering surface area. This area is presented by the outermost portion 260 of the inner surface of a ring 26 which is set in an annular recess or groove within the trumpet-shaped end.

Each ring 26 is located approximately halfway between the outer perimeter of the relevant trumpet-shaped flare 21b and the geometrical center C of the twist head 14.

The friction-engendering rings 26 must essentially be of an extremely hard-wearing material. It is at present believed that a ceramic or a suitably hard or hardened abrasion-resistant metal will be required to withstand wear from yarns or threads continuously running over the bands or rings.

It will be noted that a yarn Y travelling in the direction of the arrows diagonally through the twist head 14 and thus transversely to its axis a of rotation not only has its respectively opposite sides frictionally contacted by localized frictionengendering surface portions a moving in respectively opposite directions, but is also so supported by spaced portions of the outwardly flared convex surfaces 21b as to ensure its maximum contact with the friction rings 26.

As mentioned above, in the processing unit P, two travelling yarns or threads Y and Y are passed in opposite directions through the head, the said yarns or threads being simultaneously twisted respectively opposite hand by virtue of having intersecting diagonally opposed portions maintained in contact with the relevant friction rings 26 at opposite sides of the head. The enlargement 25a of the central opening 25 provides the room necessary to ensure that the intersecting diagonally opposed portions of the said two yarns or threads, by virtue of being unsupported at this location, shall pass freely and without any obstruction from one flared end of the twist head to the other.

The illustrated twist head 14 is driven by an electric motor constituting an actual part of the head. Although any appropriate form of electric motor may be employed for this purpose, a four-pole shaded pole motor is found to be eminently satisfactory. Thus, the rotor 27 of such a motor is interposed between the rotary ball bearing races 23a and is secured to the bush 22. The laminated stator of the motor, indicated at 28, is firmly clamped in position between pairs of lateral lugs 24a and 24b of the two housing plates or blocks 24. The heads of bolts passed right through these pairs of lugs and interposed portions of the stator are designated 29. The rotor 27 rotates within the stator 28 and there are associated with the latter two magnetic field-inducing cools 30 and 31 disposed at respectively opposite sides of the said rotor. The motor may conveniently be wholly encased within a casing 32 through which the outer portions of the trumpet-shaped ends 2111 protrude.

The reason why a shaded pole type of motor is so satisfactory is that the stator is only about half an inch in width, this enabling a twist head to be kept desirably narrow and commensurately small in diameter.

The speed of the comparatively large number (i.e. l6) twist heads 14 employed in the unit P is controlled by a frequency converter designed to change the frequency of the electrical supply.

As will be appreciated, it is necessary to stop the twist heads 14 rotating practically instantaneously with stoppage of the knitting machine K. The twist heads may therefore have combined therewith, braking means of any appropriate character. Although such means may include electrically or/and electronically operated mechanical brakes adapted to bear, when applied, upon any convenient rotating parts of the twist heads, it is preferred to incorporate the electric motors of the twist heads in electric or/and electronic circuitry having means for effecting such a change in the characteristics of the current applied to the motors as to apply braking forces to the rotors thereof. For example, these means may function to convert AC current normally applied to the motors with a counter DC current of substantially reduced voltage. Thus, with an AC current nominally of, say, 250 volts which is rectified and transformed to a counter DC current of only volts, it is possible to stop a twist head rotating in a matter of 1 second. In any event, the braking means is preferably arranged to operate and arrest the twist heads 14 as soon as the yarns and heaters are separated, when the unit P is stopped.

It will be realized that in order to cater for stopping and starting of the processing unit P, means must be provided to separate the yarns Y and heaters 13 to prevent damage to the yarns due to excessive heating. In the illustrated embodiment, these means are constituted by U-shaped yarn guides 33 (FIGS. 3 and 4), disposed one adjacent each opposite end of each heater 13, these guides being movable in directions to lift the yams Y off the heaters 13 at required times. The guides 33 associated with the vertically disposed heaters 13 are carried by axially movable horizontal rods 34, the inner ends of which bear against either an upper or a lower cam piece 35 in the shape of truncated cone. These cam pieces 35 are mounted on a common vertical shaft 36 at the center of the unit P, which is axially movable between two positions by a solenoid 37. In the lower position of shaft 36, the guides 33 are retracted and allow the yarns to run on the heaters 13, movement of the shaft to its upper position upon energization of solenoid 37, causing the cam pieces 35 to rise and force the rods 34 axially outwards to lift the yarns Y off the heaters.

The yarn guides 33 associated with the horizontal heaters 13 have stems 33a which are vertically movable in bearings (not shown), the lower ends of these stems each bearing against a wedge-shaped cam-piece 38 on the corresponding rod 34, the arrangement being such that outward axial movement of the rods 34 as described, causes the cam pieces 38 to force stems 13a upwards and lift the yarns Y away from the horizontal heaters 13.

With this direct method of yarn delivery, the processed yarn is drawn into the knitting machine K by the knitting instruments, e.g. needles. The machine draws its supplies of yarn from the bobbins I wound with flat, i.e. unprocessed, yarns which are pulled through the twist heads 14 and the heaters 13 comprising the processing unit P. By the time the yarns reach the knitting elements they have been processed and become fully developed stretch or bulk yarns.

In order to ensure that the yarns entering the machine K are subject to a predetermined tension, each yarn is, immediately prior to entering a feeder of the knitting machine, passed around about one third of the circumference of the driven shaft 39 of a compensator device 40.

Referring initially to FIG. 7, the device 40 shown therein is of similar construction to a twist head 14, being driven by a four-pole shaded pole motor. Thus it comprises the abovementioned shaft 39, which is mounted to rotate in bearings 41, the outer race 41a of which is carried by a pair of housing plates or blocks 42. The rotor 43 of the motor is secured to the shaft between the bearings 41 and the stator 44 is mounted between lugs (not shown) of plates or blocks 42 in similar fashion to the mounting of stator 28 in FIG. 5. Thus, the rotor 43 can rotate within the stator 44. Associated with the latter are two magnetic field-inducing coils 45 and 46 disposed at respectively opposite sides of the rotor. A casing 47 surrounds the device.

A modified form of compensator device is illustrated in FIG. 7a. This device is of generally similar construction to that shown in FIG. 7 and similar reference numerals have been used to denote like parts, the difference in the modified device being that instead of shaft 39, the yarn runs over the surface of a rotary cone 48. As can be seen, the device in fact includes two cones 48 which project from opposite sides thereof and are mounted on a common threaded spindle 49 arranged to be driven by the motor of the device. The cones 48 are internally screw threaded so that they can be screwed along spindle 49 to adjusted positions and locked in these positions by nuts 50.

A shaft 51 is mounted on the casing 47 of this device and carries at each end, at the side of the unit, a yarn glide 52. In use, a yarn runs over the surface of each rotating cone 48, yarn guides 52 serving to keep the yarn on the portion of the cone 48 at which it is driven at the required speed.

It will be appreciated that the advantages of using the cones 48 is that the speed at which the yarn is driven can be varied by altering the axial position on the cone at which the yarn is driven. In the illustrated embodiment, this variation is achieved by adjusting the positions of the cones 48 on spindle 49. It could, of course, be achieved by moving the yarn guides 52 instead of the cones 48. Thus, in this case, the cones 48 could be fixedly mounted on a rotary spindle or shaft and the ends of the yarn guides 52 could be internally screw threaded and mounted on portions of shaft 51 which are formed with respectively left-and right-hand screw threads. In this event turning of shaft 51, e.g. manually by means of a knurled knob, would cause the guides 52 to be moved towards or away from one another depending on the direction of turning to vary the axial positions of the yarns on the cones 48.

Using a compensator unit of the form illustrated in FIG. 70, it is possible to apply a predetermined tension to the yarn before it is fed into the processing unit P by causing yarn leaving a bobbin 1 to run through a yarn guide and over the surface of a cone 48 at an appropriate position therealong before passing into the unit P. On leaving the latter, the same yarn would pass over the same cone 48 at a different axial position therealong. In such an arrangement, each compensator device 40 would preferably be positioned midway between the two bottom twist heads of each twist head/heater assembly.

In any event, the speed of the compensator shafts 39 or cones 48 may be controlled by the same frequency converter as the twist heads 14. In one example, the knitting machine K may be running at, say 600 feet per minute and the compensator shafts 39 at 5,000 rpm. If the diameter of each shaft is one half inch, the linear speed of the surface of each shaft is 654 feet per minute so that the yarn is overdriven and has a predetermined tension applied thereto.

Reference will now be made to FIGS. 8 and 9 which illustrate a different embodiment of the said means for producing relative movement between the heaters and the yarns. In this case, the yarn guides 33 and associated actuating mechanism of the previous embodiment is omitted and each heater 13 is mounted on a support 53 through spring-loaded headed pins 54 which pass through the latter. An actuator 55 of any convenient form is provided to adjust the spacing of the heater 13 from its support and apply it against or withdraw it from the yarn. Conveniently, this actuator is constituted by a motorized screw.

In this embodiment, the yarns passing over the heaters 13 each run in contact with a band 56 of fiber-glass tape impregnated with P.T.F.E. (see above) which is separate from the heater 13. The ends of this tape are each mounted on a spool 57 located adjacent the respectively opposite ends of the heater 13 and the spools are biassed in opposite rotational directions by springs (not shown) so that the tape tends to assume a straight line configuration. (FIG. 8). However, when the heater 13 is moved towards the yarn Y, the band 56 is caused to assume the arcuate configuration of the surface of the heater.

FIG. 8 shows the heater 13 withdrawn clear of the yarn Y, eg when the unit P is stationary, and FIG. 9 shows the heater applied against the yarn Y.

The advantage of this arrangement over that of the previous embodiment is that the spacing between the heater and yarn is infinitely variable. This enables processing of the yarn to be controlled more accurately to cater for variation in the speed of takeup of the yarn by the machine K, i.e. the heaters will be moved towards the yarns as the takeup speed increases and will be withdrawn from the latter as the speed decreases, being finally moved clear of the yarns if the latter come to rest. In addition, the length of the heating path over which the yarn travels can be infinitely varied by adjusting the position of the heater relative to the yarn.

Irrespective of whether the yarn lift-off arrangement or the arrangement of FIGS. 8 and 9 is used, separation of the yarns and heaters is preferably effected, automatically when the unit is stopped. Thus, either the solenoid 37 in FIG. 3 or actuator 55 in FIGS. 8 and 9 may be so connected in the control circuitry of the unit as to be activated when the unit is stopped.

We claim:

I. An apparatus comprising, a textile machine having elements for forming yarn into fabric, and a processing unit which is intimately associated with the machine and from which processed yarns are drawn by said elements at a speed which varies with their requirements, the processing unit comprising a plurality of rotary twist heads through each of which passes a yarn to be twisted; means for driving said heads in rotation to twist the yarns to the extent of relatively large number of turns per inch; heaters which are associated with the twist heads and along which the twisted yarns are heated, the latter being allowed to set in a false-twisted condition in travelling to the textile machine and means for effecting relative movement between the yarns and heaters to respectively bring the latter into and out of a working relationship and enable the supply of yarn to be performed intermittently and at varying speeds.

2. Apparatus according to claim 1, wherein the twist heads each comprise a rotary annular component having a relatively small central opening which extends axially and merges into and connects ends (constituting the opposite sides of the twist head,) these ends being trumpet-shaped and each presenting an outwardly flared convex surface of annular form extending around an arc of substantially the said surfaces and the intermediate central opening connecting them being so related that a yarn or thread caused to travel diagonally through the component in a direction transverse to its axis of rotation not only has its respectively opposite sides frictionally contacted by surface portions moving in respectively opposite directions, but is supported for the major part of the distance both between the outer perimeter of the trumpet-shaped flare at one side of the head and the geometrical center of the latter and also between the said center and the outer perimeter of the similar flare at the opposite side of the head, whereby the yarn is fully controlled within the twist head and the twist generated in the yarn is prevented from springing through the twist head and so being nullified.

3. Apparatus according to claim 2, wherein the outwardly flared annular convex surface of each trumpet-shaped end of each twist head is adapted to present therearound, only a comparatively narrow and thus localized effective friction-engendering surface area, the remainder of the convex surface being so smooth that the friction engendered thereby is practically negligible.

4. Apparatus according to claim 3, wherein the trumpet shaped ends of each twist head constitute extensions of. the rotor of an electric motor incorporated in the head, the arrangement being such that a yarn or thread to be twisted passes through the rotor and the degree of twist imparted is determined by the motor speed.

5. Apparatus according to claim 1, wherein each twist head is so formed that a yarn entering it in one direction and in the course of being twisted by that head can leave the latter either in the same general direction or in a direction at an angle with respect to the first, the heads being so arranged in relation to the heaters as to cause a yarn leaving a twist head and about to enter and pass through or over a heater, to change direction whilst the twist in the yarn continues to build up in contradistinction to being suppressed.

6. Apparatus according to claim I, wherein each yarn, in travelling through the processing unit, passes successively through four twist heads and over or through three heaters, one being interposed between each pair of the twist heads.

7. Apparatus according to claim 6, wherein the heaters interposed between each pair of twist heads are arranged in a common vertical plane in positions defining three sides of a rectangle, with the twist heads disposed at the corners of the latter, so that each yarn in the unit passes initially vertically upwards, then horizontally and finally vertically downwards and on to the knitting or other textile machine.

8. Apparatus according to claim I, wherein the surface of each heater over which the yarn runs is constituted by a woven fiber-glass type impregnated with polytetrafluoro-ethylene.

9. In combination, a textile machine having elements for forming yarn into fabric, and a processing unit which is inti mately associated with the machine and from which processed yarns are fed to the latter, the processing unit comprising a plurality of rotary twist heads through each of which passes a yarn to be twisted; means for driving said heads in rotation to twist the yarns to the extent of a relatively large number of turns per inch; heaters which are associated with the twist heads and along which the twisted yarns are heated; means for effecting relative movement between the yarn and heaters to respectively bring the latter into and out of a working relationship and enable the supply of yarns to be performed intermittently; and means for feeding the yarn from the processing unit to the machine according to the requirements of the yarn forming elements of the latter so as to be supplied to the machine under controlled tension.

10. Apparatus according to claim 9, wherein the means for effecting relative movement between the yarns and heaters comprise a yarn guide at or adjacent each opposite end of each heater, said guides being movable simultaneously in directions to lift the yarns they guide, off the heaters.

11. Apparatus according to claim 10, wherein movement of all the yarn guides to lift the yarns off the heaters is derived, by cam means, from a common vertically movable shaft.

12. Apparatus according to claim 9, wherein means are provided for braking the twist heads simultaneously with the operation of said means for effecting relative movement between the yarns and heaters to bring the latter out of a working relationship.

13. Apparatus according to claim 9, wherein the compensator means comprises at least one compensator device comprising a shaft over which the yarn runs in surface contact, the shaft being driven in rotation at a speed such that the linear speed of its surface is in excess of the linear speed of the yarn.

14. Apparatus according to claim 9, wherein the processing unit is mounted on a removable frame which surrounds the textile machine and serves to position the unit above the latter, the frame carrying bobbins of unprocessed yarn to be supplied to the machine via the unit.

15. Apparatus according to claim 14, wherein the frame is telescopic so as to be collapsible at required times to reduce its overall height and facilitate access to the processing unit mounted thereon, spring means being provided to bias the frame into a normal, fully extended condition.

16. The invention of claim 9, in which the means for feeding the yarn includes a compensator means to which each yarn is delivered before entering the machine and by which the yarn is overdriven. 

1. An apparatus comprising, a textile machine having elements for forming yarn into fabric, and a processing unit which is intimately associated with the machine and from which processed yarns are drawn by said elements at a speed which varies with their requirements, the processing unit comprising a plurality of rotary twist heads through each of which passes a yarn to be twisted; means for driving said heads in rotation to twist the yarns to the extent of relatively large number of turns per inch; heaters which are associated with the twist heads and along which the twisted yarns are heated, the latter being allowed to set in a false-twisted condition in travelling to the textile machine and means for effecting relative movement between the yarns and heaters to respectively bring the latter into and out of a working relationship and enable the supply of yarn to be performed intermittently and at varying speeds.
 2. Apparatus according to claim 1, wherein the twist heads each comprise a rotary annular component having a relatively small central Opening which extends axially and merges into and connects ends (constituting the opposite sides of the twist head, ) these ends being trumpet-shaped and each presenting an outwardly flared convex surface of annular form extending around an arc of substantially 90*, the said surfaces and the intermediate central opening connecting them being so related that a yarn or thread caused to travel diagonally through the component in a direction transverse to its axis of rotation not only has its respectively opposite sides frictionally contacted by surface portions moving in respectively opposite directions, but is supported for the major part of the distance both between the outer perimeter of the trumpet-shaped flare at one side of the head and the geometrical center of the latter and also between the said center and the outer perimeter of the similar flare at the opposite side of the head, whereby the yarn is fully controlled within the twist head and the twist generated in the yarn is prevented from springing through the twist head and so being nullified.
 3. Apparatus according to claim 2, wherein the outwardly flared annular convex surface of each trumpet-shaped end of each twist head is adapted to present therearound, only a comparatively narrow and thus localized effective friction-engendering surface area, the remainder of the convex surface being so smooth that the friction engendered thereby is practically negligible.
 4. Apparatus according to claim 3, wherein the trumpet shaped ends of each twist head constitute extensions of the rotor of an electric motor incorporated in the head, the arrangement being such that a yarn or thread to be twisted passes through the rotor and the degree of twist imparted is determined by the motor speed.
 5. Apparatus according to claim 1, wherein each twist head is so formed that a yarn entering it in one direction and in the course of being twisted by that head can leave the latter either in the same general direction or in a direction at an angle with respect to the first, the heads being so arranged in relation to the heaters as to cause a yarn leaving a twist head and about to enter and pass through or over a heater, to change direction while the twist in the yarn continues to build up in contradistinction to being suppressed.
 6. Apparatus according to claim 1, wherein each yarn, in travelling through the processing unit, passes successively through four twist heads and over or through three heaters, one being interposed between each pair of the twist heads.
 7. Apparatus according to claim 6, wherein the heaters interposed between each pair of twist heads are arranged in a common vertical plane in positions defining three sides of a rectangle, with the twist heads disposed at the corners of the latter, so that each yarn in the unit passes initially vertically upwards, then horizontally and finally vertically downwards and on to the knitting or other textile machine.
 8. Apparatus according to claim 1, wherein the surface of each heater over which the yarn runs is constituted by a woven fiber-glass type impregnated with polytetrafluoro-ethylene.
 9. In combination, a textile machine having elements for forming yarn into fabric, and a processing unit which is intimately associated with the machine and from which processed yarns are fed to the latter, the processing unit comprising a plurality of rotary twist heads through each of which passes a yarn to be twisted; means for driving said heads in rotation to twist the yarns to the extent of a relatively large number of turns per inch; heaters which are associated with the twist heads and along which the twisted yarns are heated; means for effecting relative movement between the yarn and heaters to respectively bring the latter into and out of a working relationship and enable the supply of yarns to be performed intermittently; and means for feeding the yarn from the processing unit to the machine according to the requirements of the yarn forming elements of the latter so as to be supplied to the machine under controlled tension.
 10. Apparatus according to claim 9, wherein the means for effecting relative movement between the yarns and heaters comprise a yarn guide at or adjacent each opposite end of each heater, said guides being movable simultaneously in directions to lift the yarns they guide, off the heaters.
 11. Apparatus according to claim 10, wherein movement of all the yarn guides to lift the yarns off the heaters is derived, by cam means, from a common vertically movable shaft.
 12. Apparatus according to claim 9, wherein means are provided for braking the twist heads simultaneously with the operation of said means for effecting relative movement between the yarns and heaters to bring the latter out of a working relationship.
 13. Apparatus according to claim 9, wherein the compensator means comprises at least one compensator device comprising a shaft over which the yarn runs in surface contact, the shaft being driven in rotation at a speed such that the linear speed of its surface is in excess of the linear speed of the yarn.
 14. Apparatus according to claim 9, wherein the processing unit is mounted on a removable frame which surrounds the textile machine and serves to position the unit above the latter, the frame carrying bobbins of unprocessed yarn to be supplied to the machine via the unit.
 15. Apparatus according to claim 14, wherein the frame is telescopic so as to be collapsible at required times to reduce its overall height and facilitate access to the processing unit mounted thereon, spring means being provided to bias the frame into a normal, fully extended condition.
 16. The invention of claim 9, in which the means for feeding the yarn includes a compensator means to which each yarn is delivered before entering the machine and by which the yarn is overdriven. 